
Obviously it was a long time ago now, but when we flew our hounds from the UK to Canada all they needed was a Health Certificate (done within a certain time of them flying) and their Export papers from the KC so they could be registered with the Canadian KC. I opted not to have rabies done until we arrived, not wanting to cause any more stress than necessary. The puppy will have to be microchipped, by you as the breeder at around 8 weeks (?) in any case.
However, you do realise how long the flight will be? My friend who lives nearly Dallas FW, and is British, comes back regularly to visit her mother and flies internally to NY and on to London and in reverse when she goes back, obviously. I'd not imagine having a puppy especially, in the cabin would be viable! For obvious reasons, much as it may be of more comfort for him to be there. Others don't agree, but I'd not fly a puppy, again especially not long-haul, at under 4 months either. But perhaps that has to do with my sensitive breed.
My UK - Canada imports were 5 months and 7 months respectively when coming to me out there from the UK and another I took (flying on the same flight) to new owners from London to Geneva - he was over 4 months, and had to travel in the hold.